It ran ok before rebuild but I had to and change petcock to stop gas leak and gas in oil. Now, with stock settings it starts great, isles but sputters and dies as soon as give it gas. Taken it apart several times to blow it out and recheck but can’t get it to run. Diaphragm looks good! One question, can I run it not connected to airbox to more easily get to air mixture screw and take on an off more quickly